macro boot.janet on line 614, column 1 (if-let bindings tru &opt fal) Make multiple bindings, and if all are truthy, evaluate the tru form. If any are false or nil, evaluate the fal form. Bindings have the same syntax as the let macro.
(if-let [x true y (not (not x))] :a :b) # => :a
(if-let [x true y (not x)] :a :b) # => :b